The recording of aphid flight patterns over nine years in Canterbury (Close and Lamb, 1961 and Lowe, 1968) for a number of aphids tha t a re pests of crops, gave opportunity fo r fur ther exploration of this technique. I t appeared to have application to carrot crops, since the carrot aphid (Cavariella aegopodii Scop.) flies strongly in spring, but flights a re of a very low incidence a f te r the end of November, a s shown by 21 sets of annual trapping data from three sites in Canterbury (fig. 1 ) . Smith e t a1 (1960) had examined the effects of motley dwarf virus in carrots, and recorded tests showing the carrot aphid as vector. Some of the most popular carrot varieties were the worst affected, and were abandoned by growers.